Skip canonicalization check in LStoreKeyedFastDoubleElement when it is not needed:

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 3bb4ebc99407c337f0651eddfe2c4ea68f13c121..f02fd10a55a22d113ff466a87b25151fb7085a6a 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -2090,6 +2090,17 @@ HValue* HAdd::EnsureAndPropagateNotMinusZero(BitVector* visited) {
 }
 
 
+bool HStoreKeyedFastDoubleElement::NeedsCanonicalization() {
+  // If value was loaded from unboxed double backing store or
+  // converted from an integer then we don't have to canonicalize it.
+  if (value()->IsLoadKeyedFastDoubleElement() ||
+      (value()->IsChange() && HChange::cast(value())->from().IsInteger32())) {
+    return false;
+  }
+  return true;
+}
+
+
 #define H_CONSTANT_INT32(val)                                                  \
 new(zone) HConstant(FACTORY->NewNumberFromInt(val, TENURED),                   \
                     Representation::Integer32())